Lost 17 GB after installing Windows update 2004

I successfully downloaded and installed the latest windows update 2004 yesterday. Everything is working perfectly. However, I notice that when I look at my C: drive that my free space has dropped from about 60GB to 40GB. I've tried Disk Clean Up >Clean up system files, but after ticking all the boxes I saw no mention of Previous Windows Installations. I then tried Settings - System - Storage - Temporary files, but could not find the option to delete previous versions of Windows. Would anyone have a suggestion as to how I can get back my lost storage? Thank you.

 

Leave it alone as MS will remove the files after a set time.Usually after 10 days.
Do a Google on when does MS clear update files.

 

Thanks, Retiredlearner, I'll follow your advice and let the hare sit.

 

It can take up to 30 days for the windows.old file to finally disappear after the update.

Unless you are critically low on free disk space, I also recommend you just leave it. If you are critically low, and you are 200% certain you will not need to roll back to the previous version, then it is safe to simply delete windows.old. Windows own Disk Cleanup has this option. However, if you really "need" that space, deleting the windows.old file is just a band-aid fix. You need a permanent solution. That is, you need to uninstall a bunch of unused programs, and/or move or delete a bunch of unneeded files, or better yet, buy more space.